draft-ietf-ccamp-flexi-grid-fwk-03.txt   draft-ietf-ccamp-flexi-grid-fwk-04.txt 
Network Working Group O. Gonzalez de Dios, Ed. CCAMP Working Group O. Gonzalez de Dios, Ed.
Internet-Draft Telefonica I+D Internet-Draft Telefonica I+D
Intended status: Standards Track R. Casellas, Ed. Intended status: Informational R. Casellas, Ed.
Expires: August 27, 2015 CTTC Expires: November 19, 2015 CTTC
F. Zhang F. Zhang
Huawei Huawei
X. Fu X. Fu
ZTE ZTE
D. Ceccarelli D. Ceccarelli
Ericsson Ericsson
I. Hussain I. Hussain
Infinera Infinera
February 23, 2015 May 18, 2015
Framework and Requirements for GMPLS-based control of Flexi-grid DWDM Framework and Requirements for GMPLS-based control of Flexi-grid DWDM
networks networks
draft-ietf-ccamp-flexi-grid-fwk-03 draft-ietf-ccamp-flexi-grid-fwk-04
Abstract Abstract
To allow efficient allocation of optical spectral bandwidth for high To allow efficient allocation of optical spectral bandwidth for high
bit-rate systems, the International Telecommunication Union bit-rate systems, the International Telecommunication Union
Telecommunication Standardization Sector (ITU-T) has extended its Telecommunication Standardization Sector (ITU-T) has extended its
Recommendations G.694.1 and G.872 to include a new dense wavelength Recommendations G.694.1 and G.872 to include a new dense wavelength
division multiplexing (DWDM) grid by defining a set of nominal division multiplexing (DWDM) grid by defining a set of nominal
central frequencies, channel spacings and the concept of "frequency central frequencies, channel spacings and the concept of "frequency
slot". In such an environment, a data plane connection is switched slot". In such an environment, a data plane connection is switched
skipping to change at page 2, line 7 skipping to change at page 2, line 7
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
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and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
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This Internet-Draft will expire on August 27, 2015. This Internet-Draft will expire on November 19, 2015.
Copyright Notice Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the Copyright (c) 2015 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1. Requirements Language . . . . . . . . . . . . . . . . . . 4 2.1. Requirements Language . . . . . . . . . . . . . . . . . . 4
2.2. Abbreviations . . . . . . . . . . . . . . . . . . . . . . 4 2.2. Abbreviations . . . . . . . . . . . . . . . . . . . . . . 4
3. Overview of Flexi-grid Networks . . . . . . . . . . . . . . . 5 3. Overview of Flexi-grid Networks . . . . . . . . . . . . . . . 5
3.1. Flexi-grid in the Context of OTN . . . . . . . . . . . . 5 3.1. Flexi-grid in the Context of OTN . . . . . . . . . . . . 5
3.2. Flexi-grid Terminology . . . . . . . . . . . . . . . . . 6 3.2. Flexi-grid Terminology . . . . . . . . . . . . . . . . . 6
3.2.1. Frequency Slots . . . . . . . . . . . . . . . . . . . 6 3.2.1. Frequency Slots . . . . . . . . . . . . . . . . . . . 6
3.2.2. Media Channels . . . . . . . . . . . . . . . . . . . 8 3.2.2. Media Layer Elements . . . . . . . . . . . . . . . . 8
3.2.3. Media Layer Elements . . . . . . . . . . . . . . . . 8 3.2.3. Media Channels . . . . . . . . . . . . . . . . . . . 8
3.2.4. Optical Tributary Signals . . . . . . . . . . . . . . 9 3.2.4. Optical Tributary Signals . . . . . . . . . . . . . . 9
3.2.5. Composite Media Channels . . . . . . . . . . . . . . 9 3.2.5. Composite Media Channels . . . . . . . . . . . . . . 9
3.3. Hierarchy in the Media Layer . . . . . . . . . . . . . . 10 3.3. Hierarchy in the Media Layer . . . . . . . . . . . . . . 10
3.4. Flexi-grid Layered Network Model . . . . . . . . . . . . 10 3.4. Flexi-grid Layered Network Model . . . . . . . . . . . . 10
3.4.1. DWDM Flexi-grid Enabled Network Element Models . . . 12 3.4.1. DWDM Flexi-grid Enabled Network Element Models . . . 12
4. GMPLS Applicability . . . . . . . . . . . . . . . . . . . . . 12 4. GMPLS Applicability . . . . . . . . . . . . . . . . . . . . . 12
4.1. General Considerations . . . . . . . . . . . . . . . . . 12 4.1. General Considerations . . . . . . . . . . . . . . . . . 12
4.2. Consideration of TE Links . . . . . . . . . . . . . . . . 13 4.2. Consideration of TE Links . . . . . . . . . . . . . . . . 13
4.3. Consideration of LSPs in Flexi-grid . . . . . . . . . . . 16 4.3. Consideration of LSPs in Flexi-grid . . . . . . . . . . . 15
4.4. Control Plane Modeling of Network Elements . . . . . . . 21 4.4. Control Plane Modeling of Network Elements . . . . . . . 20
4.5. Media Layer Resource Allocation Considerations . . . . . 21 4.5. Media Layer Resource Allocation Considerations . . . . . 20
4.6. Neighbor Discovery and Link Property Correlation . . . . 25 4.6. Neighbor Discovery and Link Property Correlation . . . . 24
4.7. Path Computation / Routing and Spectrum Assignment (RSA) 26 4.7. Path Computation / Routing and Spectrum Assignment (RSA) 25
4.7.1. Architectural Approaches to RSA . . . . . . . . . . . 26 4.7.1. Architectural Approaches to RSA . . . . . . . . . . . 25
4.8. Routing and Topology Dissemination . . . . . . . . . . . 27 4.8. Routing and Topology Dissemination . . . . . . . . . . . 26
4.8.1. Available Frequency Ranges/Slots of DWDM Links . . . 28 4.8.1. Available Frequency Ranges/Slots of DWDM Links . . . 27
4.8.2. Available Slot Width Ranges of DWDM Links . . . . . . 28 4.8.2. Available Slot Width Ranges of DWDM Links . . . . . . 27
4.8.3. Spectrum Management . . . . . . . . . . . . . . . . . 28 4.8.3. Spectrum Management . . . . . . . . . . . . . . . . . 27
4.8.4. Information Model . . . . . . . . . . . . . . . . . . 28 4.8.4. Information Model . . . . . . . . . . . . . . . . . . 27
5. Control Plane Requirements . . . . . . . . . . . . . . . . . 30 5. Control Plane Requirements . . . . . . . . . . . . . . . . . 29
5.1. Support for Media Channels . . . . . . . . . . . . . . . 30 5.1. Support for Media Channels . . . . . . . . . . . . . . . 29
5.1.1. Signaling . . . . . . . . . . . . . . . . . . . . . . 31 5.1.1. Signaling . . . . . . . . . . . . . . . . . . . . . . 30
5.1.2. Routing . . . . . . . . . . . . . . . . . . . . . . . 31 5.1.2. Routing . . . . . . . . . . . . . . . . . . . . . . . 30
5.2. Support for Media Channel Resizing . . . . . . . . . . . 32 5.2. Support for Media Channel Resizing . . . . . . . . . . . 31
5.3. Support for Logical Associations of Multiple Media 5.3. Support for Logical Associations of Multiple Media
Channels . . . . . . . . . . . . . . . . . . . . . . . . 32 Channels . . . . . . . . . . . . . . . . . . . . . . . . 31
5.4. Support for Composite Media Channels . . . . . . . . . . 32 5.4. Support for Composite Media Channels . . . . . . . . . . 31
5.5. Support for Neighbor Discovery and Link Property 5.5. Support for Neighbor Discovery and Link Property
Correlation . . . . . . . . . . . . . . . . . . . . . . . 32 Correlation . . . . . . . . . . . . . . . . . . . . . . . 31
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 33 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 32
7. Security Considerations . . . . . . . . . . . . . . . . . . . 33 7. Security Considerations . . . . . . . . . . . . . . . . . . . 32
8. Manageability Considerations . . . . . . . . . . . . . . . . 33 8. Manageability Considerations . . . . . . . . . . . . . . . . 32
9. Contributing Authors . . . . . . . . . . . . . . . . . . . . 34 9. Contributing Authors . . . . . . . . . . . . . . . . . . . . 33
10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 37 10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 36
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 37 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 36
11.1. Normative References . . . . . . . . . . . . . . . . . . 37 11.1. Normative References . . . . . . . . . . . . . . . . . . 36
11.2. Informative References . . . . . . . . . . . . . . . . . 38 11.2. Informative References . . . . . . . . . . . . . . . . . 37
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 39 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 38
1. Introduction 1. Introduction
The term "Flexible grid" (flexi-grid for short) as defined by the The term "Flexible grid" (flexi-grid for short) as defined by the
International Telecommunication Union Telecommunication International Telecommunication Union Telecommunication
Standardization Sector (ITU-T) Study Group 15 in the latest version Standardization Sector (ITU-T) Study Group 15 in the latest version
of [G.694.1], refers to the updated set of nominal central of [G.694.1], refers to the updated set of nominal central
frequencies (a frequency grid), channel spacing and optical spectrum frequencies (a frequency grid), channel spacing and optical spectrum
management/allocation considerations that have been defined in order management/allocation considerations that have been defined in order
to allow an efficient and flexible allocation and configuration of to allow an efficient and flexible allocation and configuration of
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optical spectrum frequency ranges or frequency slots with typical optical spectrum frequency ranges or frequency slots with typical
channel separations of 50 GHz, a flexible grid network can select its channel separations of 50 GHz, a flexible grid network can select its
media channels with a more flexible choice of slot widths, allocating media channels with a more flexible choice of slot widths, allocating
as much optical spectrum as required. as much optical spectrum as required.
From a networking perspective, a flexible grid network is assumed to From a networking perspective, a flexible grid network is assumed to
be a layered network [G.872][G.800] in which the media layer is the be a layered network [G.872][G.800] in which the media layer is the
server layer and the optical signal layer is the client layer. In server layer and the optical signal layer is the client layer. In
the media layer, switching is based on a frequency slot, and the size the media layer, switching is based on a frequency slot, and the size
of a media channel is given by the properties of the associated of a media channel is given by the properties of the associated
frequency slot. In this layered network, the media channel can frequency slot. In this layered network, a media channel can
transport more than one Optical Tributary Signals. transport more than one Optical Tributary Signals (OTSi), as defined
later in this document.
A Wavelength Switched Optical Network (WSON), addressed in [RFC6163], A Wavelength Switched Optical Network (WSON), addressed in [RFC6163],
is a term commonly used to refer to the application/deployment of a is a term commonly used to refer to the application/deployment of a
GMPLS-based control plane for the control (provisioning/recovery, GMPLS-based control plane for the control (provisioning/recovery,
etc.) of a fixed grid wavelength division multiplexing (WDM) network etc.) of a fixed grid wavelength division multiplexing (WDM) network
in which media (spectrum) and signal are jointly considered. in which media (spectrum) and signal are jointly considered.
This document defines the framework for a GMPLS-based control of This document defines the framework for a GMPLS-based control of
flexi-grid enabled dense wavelength division multiplexing (DWDM) flexi-grid enabled dense wavelength division multiplexing (DWDM)
networks (in the scope defined by ITU-T layered Optical Transport networks (in the scope defined by ITU-T layered Optical Transport
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FS: Frequency Slot FS: Frequency Slot
FSC: Fiber-Switch Capable FSC: Fiber-Switch Capable
LSR: Label Switching Router LSR: Label Switching Router
NCF: Nominal Central Frequency NCF: Nominal Central Frequency
OCh: Optical Channel OCh: Optical Channel
OCh-P: Optical Channel Payload OCh-P: Optical Channel Payload
OTN: Optical Transport Network
OTSi: Optical Tributary Signal OTSi: Optical Tributary Signal
OTSiG: OTSi Group is the set of OTSi signals OTSiG: OTSi Group is a set of OTSi
OCC: Optical Channel Carrier OCC: Optical Channel Carrier
PCE: Path Computation Element PCE: Path Computation Element
ROADM: Reconfigurable Optical Add-Drop Multiplexer ROADM: Reconfigurable Optical Add-Drop Multiplexer
SSON: Spectrum-Switched Optical Network SSON: Spectrum-Switched Optical Network
SWG: Slot Width Granularity SWG: Slot Width Granularity
3. Overview of Flexi-grid Networks 3. Overview of Flexi-grid Networks
3.1. Flexi-grid in the Context of OTN 3.1. Flexi-grid in the Context of OTN
[G.872] describes, from a network level, the functional architecture [G.872] describes, from a network level, the functional architecture
of Optical Transport Networks (OTN). The OTN is decomposed into of an OTN. It is decomposed into independent layer networks with
independent layer networks with client/layer relationships among client/layer relationships among them. A simplified view of the OTN
them. A simplified view of the OTN layers is shown in Figure 1. layers is shown in Figure 1.
+----------------+ +----------------+
| Digital Layer | | Digital Layer |
+----------------+ +----------------+
| Signal Layer | | Signal Layer |
+----------------+ +----------------+
| Media Layer | | Media Layer |
+----------------+ +----------------+
Figure 1: Generic OTN Overview Figure 1: Generic OTN Overview
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This section presents the definition of the terms used in flexi-grid This section presents the definition of the terms used in flexi-grid
networks. More detail about these terms can be found in the ITU-T networks. More detail about these terms can be found in the ITU-T
Recommendations [G.694.1], [G.872]), [G.870], [G.8080], and Recommendations [G.694.1], [G.872]), [G.870], [G.8080], and
[G.959.1-2013]. [G.959.1-2013].
Where appropriate, this documents also uses terminology and Where appropriate, this documents also uses terminology and
lexicography from [RFC4397]. lexicography from [RFC4397].
3.2.1. Frequency Slots 3.2.1. Frequency Slots
This subsection is focused on the frequency slot related terms. This subsection is focused on the frequency slot and related terms.
o Frequency Slot [G.694.1]: The frequency range allocated to a slot o Frequency Slot [G.694.1]: The frequency range allocated to a slot
within the flexible grid and unavailable to other slots. A within the flexible grid and unavailable to other slots. A
frequency slot is defined by its nominal central frequency and its frequency slot is defined by its nominal central frequency and its
slot width. slot width.
o Effective Frequency Slot [G.870]: The effective frequency slot of
a media channel is that part of the frequency slots of the filters
along the media channel that is common to all of the filters'
frequency slots. Note that both the Frequency Slot and Effective
Frequency Slot are both local terms.
o Nominal Central Frequency: Each of the allowed frequencies as per o Nominal Central Frequency: Each of the allowed frequencies as per
the definition of flexible DWDM grid in [G.694.1]. The set of the definition of flexible DWDM grid in [G.694.1]. The set of
nominal central frequencies can be built using the following nominal central frequencies can be built using the following
expression expression
f = 193.1 THz + n x 0.00625 THz f = 193.1 THz + n x 0.00625 THz
where 193.1 THz is ITU-T "anchor frequency" for transmission over where 193.1 THz is ITU-T "anchor frequency" for transmission over
the C band, and n is a positive or negative integer including 0. the C band, and n is a positive or negative integer including 0.
-5 -4 -3 -2 -1 0 1 2 3 4 5 <- values of n -5 -4 -3 -2 -1 0 1 2 3 4 5 <- values of n
...+--+--+--+--+--+--+--+--+--+--+- ...+--+--+--+--+--+--+--+--+--+--+-
^ ^
193.1 THz <- anchor frequency 193.1 THz <- anchor frequency
Figure 2: Anchor Frequency and Set of Nominal Central Frequencies Figure 2: Anchor Frequency and Set of Nominal Central Frequencies
o Nominal Central Frequency Granularity: This is the spacing between o Nominal Central Frequency Granularity: This is the spacing between
allowed nominal central frequencies and it is set to 6.25 GHz. allowed nominal central frequencies and it is set to 6.25 GHz
[G.694.1].
o Slot Width Granularity (SWG): 12.5 GHz, as defined in [G.694.1]. o Slot Width Granularity (SWG): 12.5 GHz, as defined in [G.694.1].
o Slot Width: The slot width determines the "amount" of optical o Slot Width: The slot width determines the "amount" of optical
spectrum regardless of its actual "position" in the frequency spectrum regardless of its actual "position" in the frequency
axis. A slot width is constrained to be m x SWG (that is, m x axis. A slot width is constrained to be m x SWG (that is, m x
12.5 GHz), where m is an integer greater than or equal to 1. 12.5 GHz), where m is an integer greater than or equal to 1.
Frequency Slot 1 Frequency Slot 2 Frequency Slot 1 Frequency Slot 2
------------- ------------------- ------------- -------------------
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* The symbol '+' represents the allowed nominal central * The symbol '+' represents the allowed nominal central
frequencies frequencies
* The '--' represents the nominal central frequency granularity * The '--' represents the nominal central frequency granularity
* The '^' represents the slot nominal central frequency * The '^' represents the slot nominal central frequency
* The number on the top of the '+' symbol represents the 'n' in * The number on the top of the '+' symbol represents the 'n' in
the frequency calculation formula. the frequency calculation formula.
* The nominal central frequency is 193.1 THz when n equals zero. * The nominal central frequency is 193.1 THz when n equals to
zero.
o Effective Frequency Slot: The effective frequency slot of a media o Effective Frequency Slot [G.870]: The effective frequency slot of
channel is the common part of the frequency slots along the media a media channel is that part of the frequency slots of the filters
channel through a particular path through the optical network. It along the media channel that is common to all of the filters'
is a logical construct derived from the (intersection of) frequency slots. Note that both the Frequency Slot and Effective
frequency slots allocated to each device in the path. The Frequency Slot are local terms.
effective frequency slot is an attribute of a media channel and,
being a frequency slot, it is described by its nominal central
frequency and slot width, according to the already described
rules.
Frequency Slot 1 Frequency Slot 1
------------- -------------
| | | |
-3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11
..--+--+--+--+--X--+--+--+--+--+--+--+--+--+--+--+--... ..--+--+--+--+--X--+--+--+--+--+--+--+--+--+--+--+--...
Frequency Slot 2 Frequency Slot 2
------------------- -------------------
| | | |
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=============================================== ===============================================
Effective Frequency Slot Effective Frequency Slot
------------- -------------
| | | |
-3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11
..--+--+--+--+--X--+--+--+--+--+--+--+--+--+--+--+--... ..--+--+--+--+--X--+--+--+--+--+--+--+--+--+--+--+--...
Figure 4: Effective Frequency Slot Figure 4: Effective Frequency Slot
3.2.2. Media Channels 3.2.2. Media Layer Elements
o Media Element: A media element directs an optical signal or
affects the properties of an optical signal. It does not modify
the properties of the information that has been modulated to
produce the optical signal [G.870]. Examples of media elements
include fibers, amplifiers, filters, and switching matrices.
o Media Channel Matrixes: The media channel matrix provides flexible
connectivity for the media channels. That is, it represents a
point of flexibility where relationships between the media ports
at the edge of a media channel matrix may be created and broken.
The relationship between these ports is called a matrix channel.
(Network) Media Channels are switched in a Media Channel Matrix.
3.2.3. Media Channels
This section defines concepts such as (Network) Media Channel; the This section defines concepts such as (Network) Media Channel; the
mapping to GMPLS constructs (i.e., LSP) is detailed in Section 4. mapping to GMPLS constructs (i.e., LSP) is detailed in Section 4.
o Media Channel: A media association that represents both the o Media Channel: A media association that represents both the
topology (i.e., path through the media) and the resource topology (i.e., path through the media) and the resource
(frequency slot) that it occupies. As a topological construct, it (frequency slot) that it occupies. As a topological construct, it
represents a frequency slot (an effective frequency slot) represents a frequency slot (an effective frequency slot)
supported by a concatenation of media elements (fibers, supported by a concatenation of media elements (fibers,
amplifiers, filters, switching matrices...). This term is used to amplifiers, filters, switching matrices...). This term is used to
identify the end-to-end physical layer entity with its identify the end-to-end physical layer entity with its
corresponding (one or more) frequency slots local at each link corresponding (one or more) frequency slots local at each link
filters. filters.
o Network Media Channel: [G.870] defines the Network Media Channel o Network Media Channel: [G.870] defines the Network Media Channel
in terms of the media channel that transports the OTSi. This as a media channel that transports a single OTSi, defined next.
document broadens the definition to cover any OTSi so that a
Network Media Channel is a media channel that transports an OTSi.
3.2.3. Media Layer Elements
o Media Element: A media element directs an optical signal or
affects the properties of an optical signal. It does not modify
the properties of the information that has been modulated to
produce the optical signal [G.870]. Examples of media elements
include fibers, amplifiers, filters, and switching matrices.
o Media Channel Matrixes: The media channel matrix provides flexible
connectivity for the media channels. That is, it represents a
point of flexibility where relationships between the media ports
at the edge of a media channel matrix may be created and broken.
The relationship between these ports is called a matrix channel.
(Network) Media Channels are switched in a Media Channel Matrix.
3.2.4. Optical Tributary Signals 3.2.4. Optical Tributary Signals
o Optical Tributary Signal (OTSi) [G.959.1-2013]: The optical signal o Optical Tributary Signal (OTSi) [G.959.1-2013]: The optical signal
that is placed within a network media channel for transport across that is placed within a network media channel for transport across
the optical network. This may consist of a single modulated the optical network. This may consist of a single modulated
optical carrier or a group of modulated optical carriers or optical carrier or a group of modulated optical carriers or
subcarriers. To provide a connection between the OTSi source and subcarriers. To provide a connection between the OTSi source and
the OTSi sink the optical signal must be assigned to a network the OTSi sink the optical signal must be assigned to a network
media channel. media channel.
o OTSi Group (OTSiG): The set of OTSi signals that are carried by a o OTSi Group (OTSiG): The set of OTSi that are carried by a group of
group of network media channels. Each OTSi is carried by one network media channels. Each OTSi is carried by one network media
network media channel. From a management perspective it should be channel. From a management perspective it SHOULD be possible to
possible to manage both the OTSiG and a group of Network Media manage both the OTSiG and a group of Network Media Channels as
Channels as single entities. single entities.
3.2.5. Composite Media Channels 3.2.5. Composite Media Channels
o It is possible to construct an end-to-end media channel as a o It is possible to construct an end-to-end media channel as a
composite of more than one network media channels. A composite composite of more than one network media channels. A composite
media channel carries a group of OTSi (i.e., OTSiG). Each OTSi is media channel carries a group of OTSi (i.e., OTSiG). Each OTSi is
carried by one network media channel. This group of OTSi should carried by one network media channel. This group of OTSi are
be carried over a single fibre. carried over a single fibre.
o In this case, the effective frequency slots may be contiguous o In this case, the effective frequency slots may be contiguous
(i.e., there is no spectrum between them that can be used for (i.e., there is no spectrum between them that can be used for
other media channels) or non-contiguous. other media channels) or non-contiguous.
o It is not currently envisaged that such composite media channels o It is not currently envisaged that such composite media channels
may be constructed from slots carried on different fibers whether may be constructed from slots carried on different fibers whether
those fibers traverse the same hop-by-hop path through the network those fibers traverse the same hop-by-hop path through the network
or not. or not.
skipping to change at page 10, line 19 skipping to change at page 10, line 19
In summary, the concept of frequency slot is a logical abstraction In summary, the concept of frequency slot is a logical abstraction
that represents a frequency range, while the media layer represents that represents a frequency range, while the media layer represents
the underlying media support. Media Channels are media associations, the underlying media support. Media Channels are media associations,
characterized by their (effective) frequency slot, respectively; and characterized by their (effective) frequency slot, respectively; and
media channels are switched in media channel matrixes. From the media channels are switched in media channel matrixes. From the
control and management perspective, a media channel can be logically control and management perspective, a media channel can be logically
split into network media channels. split into network media channels.
In Figure 5, a media channel has been configured and dimensioned to In Figure 5, a media channel has been configured and dimensioned to
support two network media channels, each of them carrying one optical support two network media channels, each of them carrying one OTSi.
tributary signal.
Media Channel Frequency Slot Media Channel Frequency Slot
+-------------------------------X------------------------------+ +-------------------------------X------------------------------+
| | | |
| Frequency Slot Frequency Slot | | Frequency Slot Frequency Slot |
| +------------X-----------+ +----------X-----------+ | | +------------X----------+ +----------X-----------+ |
| | Opt Tributary Signal | | Opt Tributary Signal | | | | OTSi | | OTSi | |
| | o | | o | | | | o | | o | |
| | | | | | | | | | | | | | | |
-4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12
--+---+---+---+---+---+---+---+---+---+---+---+--+---+---+---+---+-- --+---+---+---+---+---+---+---+---+---+---+---+--+---+---+---+---+--
<- Network Media Channel-> <- Network Media Channel-> <- Network Media Channel-> <- Network Media Channel->
<------------------------ Media Channel -----------------------> <------------------------ Media Channel ----------------------->
X - Frequency Slot Central Frequency X - Frequency Slot Central Frequency
o - signal central frequency o - Signal Central Frequency
Figure 5: Example of Media Channel / Network Media Channels and Figure 5: Example of Media Channel / Network Media Channels and
Associated Frequency Slots Associated Frequency Slots
3.4. Flexi-grid Layered Network Model 3.4. Flexi-grid Layered Network Model
In the OTN layered network, the network media channel transports a In the OTN layered network, the network media channel transports a
single Optical Tributary Signal (see Figure 6) single OTSi (see Figure 6)
| Optical Tributary Signal | | OTSi |
O - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - O O - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - O
| | | |
| Channel Port Network Media Channel Channel Port | | Channel Port Network Media Channel Channel Port |
O - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - O O - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - O
| | | |
+--------+ +-----------+ +--------+ +--------+ +-----------+ +--------+
| \ (1) | | (1) | | (1) / | | \ (1) | | (1) | | (1) / |
| \----|-----------------|-----------|-------------------|-----/ | | \----|-----------------|-----------|-------------------|-----/ |
+--------+ Link Channel +-----------+ Link Channel +--------+ +--------+ Link Channel +-----------+ Link Channel +--------+
Media Channel Media Channel Media Channel Media Channel Media Channel Media Channel
Matrix Matrix Matrix Matrix Matrix Matrix
The symbol (1) indicates a Matrix Channel The symbol (1) indicates a Matrix Channel
Figure 6: Simplified Layered Network Model Figure 6: Simplified Layered Network Model
A particular example of Optical Tributary Signal is the OCh-P. Note that a particular example of OTSi is the OCh-P. Figure 7 shows
Figure 7 shows this specific example as defined in G.805 [G.805]. this specific example as defined in G.805 [G.805].
OCh AP Trail (OCh) OCh AP OCh AP Trail (OCh) OCh AP
O- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - O O- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - O
| | | |
--- OCh-P OCh-P --- --- OCh-P OCh-P ---
\ / source sink \ / \ / source sink \ /
+ + + +
| OCh-P OCh-P Network Connection OCh-P | | OCh-P OCh-P Network Connection OCh-P |
O TCP - - - - - - - - - - - - - - - - - - - - - - - - - - -TCP O O TCP - - - - - - - - - - - - - - - - - - - - - - - - - - -TCP O
| | | |
skipping to change at page 12, line 5 skipping to change at page 12, line 5
| \ (1) | OCh-P LC | (1) | OCh-P LC | (1) / | | \ (1) | OCh-P LC | (1) | OCh-P LC | (1) / |
| \----|-----------------|-----------|-----------------|------/ | | \----|-----------------|-----------|-----------------|------/ |
+--------+ Link Channel +-----------+ Link Channel +---------+ +--------+ Link Channel +-----------+ Link Channel +---------+
Media Channel Media Channel Media Channel Media Channel Media Channel Media Channel
Matrix Matrix Matrix Matrix Matrix Matrix
The symbol (1) indicates a Matrix Channel The symbol (1) indicates a Matrix Channel
Figure 7: Layered Network Model According to G.805 Figure 7: Layered Network Model According to G.805
By definition, a network media channel supports only a single Optical
Tributary Signal.
3.4.1. DWDM Flexi-grid Enabled Network Element Models 3.4.1. DWDM Flexi-grid Enabled Network Element Models
A flexible grid network is constructed from subsystems that include A flexible grid network is constructed from subsystems that include
WDM links, tunable transmitters, and receivers, (i.e, media elements WDM links, tunable transmitters, and receivers, (i.e, media elements
including media layer switching elements that are media matrices) as including media layer switching elements that are media matrices) as
well as electro-optical network elements. This is just the same as well as electro-optical network elements. This is just the same as
in a fixed grid network except that each element has flexible grid in a fixed grid network except that each element has flexible grid
characteristics. characteristics.
As stated in Clause 7 of [G.694.1] the flexible DWDM grid has a As stated in Clause 7 of [G.694.1] the flexible DWDM grid has a
skipping to change at page 13, line 4 skipping to change at page 12, line 50
between the architectural concept/construct of media channel and its between the architectural concept/construct of media channel and its
control plane representations (e.g., as a TE link). control plane representations (e.g., as a TE link).
4.1. General Considerations 4.1. General Considerations
The GMPLS control of the media layer deals with the establishment of The GMPLS control of the media layer deals with the establishment of
media channels that are switched in media channel matrices. GMPLS media channels that are switched in media channel matrices. GMPLS
labels are used to locally represent the media channel and its labels are used to locally represent the media channel and its
associated frequency slot. Network media channels are considered a associated frequency slot. Network media channels are considered a
particular case of media channels when the end points are particular case of media channels when the end points are
transceivers (that is, source and destination of an Optical Tributary transceivers (that is, source and destination of an OTSi).
Signal)
4.2. Consideration of TE Links 4.2. Consideration of TE Links
From a theoretical / abstract point of view, a fiber can be modeled From a theoretical / abstract point of view, a fiber can be modeled
as having a frequency slot that ranges from minus infinity to plus as having a frequency slot that ranges from minus infinity to plus
infinity. This representation helps understand the relationship infinity. This representation helps understand the relationship
between frequency slots and ranges. between frequency slots and ranges.
The frequency slot is a local concept that applies within a component The frequency slot is a local concept that applies within a component
or element. When applied to a media channel, we are referring to its or element. When applied to a media channel, we are referring to its
effective frequency slot as defined in [G.872]. effective frequency slot as defined in [G.872].
The association of the three components a filter, a fiber, and a The association sequence of the three components (i.e., a filter, a
filter, is a media channel in its most basic form. From the control fiber, and a filter), is a media channel in its most basic form.
plane perspective this may modeled as a (physical) TE-link with a From the control plane perspective this may modeled as a (physical)
contiguous optical spectrum. This can be represented by saying that TE-link with a contiguous optical spectrum. This can be represented
the portion of spectrum available at time t0 depends on which filters by saying that the portion of spectrum available at time t0 depends
are placed at the ends of the fiber and how they have been on which filters are placed at the ends of the fiber and how they
configured. Once filters are placed we have a one-hop media channel. have been configured. Once filters are placed we have a one-hop
In practical terms, associating a fiber with the terminating filters media channel. In practical terms, associating a fiber with the
determines the usable optical spectrum. terminating filters determines the usable optical spectrum.
---------------+ +-----------------+ ---------------+ +-----------------+
| | | |
+--------+ +--------+ +--------+ +--------+
| | | | +--------- | | | | +---------
---o| =============================== o--| ---o| =============================== o--|
| | Fiber | | | --\ /-- | | Fiber | | | --\ /--
---o| | | o--| \/ ---o| | | o--| \/
| | | | | /\ | | | | | /\
---o| =============================== o--| --/ \-- ---o| =============================== o--| --/ \--
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--------+ +-------- --------+ +--------
|--------------------------------------| |--------------------------------------|
LSR | TE link | LSR LSR | TE link | LSR
|--------------------------------------| |--------------------------------------|
+--------+ +-------- +--------+ +--------
Figure 8: (Basic) Media Channel and TE Link Figure 8: (Basic) Media Channel and TE Link
Additionally, when a cross-connect for a specific frequency slot is Additionally, when a cross-connect for a specific frequency slot is
considered, the underlying media support is still a media channel, considered, the resulting media support of joining basic media
augmented, so to speak, with a bigger association of media elements channels is still a media channel, i.e., a longer association
and a resulting effective slot. When this media channel is the sequence of media elements and its effective frequency slot. In
result of the association of basic media channels and media layer other words, It is possible to "concatenate" several media channels
matrix cross-connects, this architectural construct can be (e.g., patch on intermediate nodes) to create a single media channel.
The architectural construct resulting of the association sequence of
basic media channels and media layer matrix cross-connects can be
represented as (i.e., corresponds to) a Label Switched Path (LSP) represented as (i.e., corresponds to) a Label Switched Path (LSP)
from a control plane perspective. In other words, It is possible to from a control plane perspective.
"concatenate" several media channels (e.g., Patch on intermediate
nodes) to create a single media channel.
----------+ +------------------------------+ +--------- ----------+ +------------------------------+ +---------
| | | | | | | |
+------+ +------+ +------+ +------+ +------+ +------+ +------+ +------+
| | | | +----------+ | | | | | | | | +----------+ | | | |
--o| ========= o--| |--o ========= o-- --o| ========= o--| |--o ========= o--
| | Fiber | | | --\ /-- | | | Fiber | | | | Fiber | | | --\ /-- | | | Fiber | |
--o| | | o--| \/ |--o | | o-- --o| | | o--| \/ |--o | | o--
| | | | | /\ | | | | | | | | | | /\ | | | | |
--o| ========= o--***********|--o ========= o-- --o| ========= o--***********|--o ========= o--
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|------------------| |----------------| |------------------| |----------------|
LSR | TE link | LSR | TE link | LSR LSR | TE link | LSR | TE link | LSR
|------------------| |----------------| |------------------| |----------------|
-----+ +---------------+ +----- -----+ +---------------+ +-----
Figure 11: Flex-grid LSP Representing a Media Channel that Starts at Figure 11: Flex-grid LSP Representing a Media Channel that Starts at
the Filter of the Outgoing Interface of the Ingress LSR and ends at the Filter of the Outgoing Interface of the Ingress LSR and ends at
the Filter of the Incoming Interface of the Egress LSR the Filter of the Incoming Interface of the Egress LSR
In Figure 12 a Network Media Channel is represented as terminated at In Figure 12 a Network Media Channel is represented as terminated at
the DWDM side of the transponder. This is commonly named as OCh- the network side of the trnaponders. This is commonly names as OTSi-
trail connection. trail connection.
|--------------------- Network Media Channel ----------------------| |--------------------- Network Media Channel ----------------------|
+----------------------+ +----------------------+ +----------------------+ +----------------------+
| | | | | |
+------+ +------+ +------+ +------+ +------+ +------+ +------+ +------+
| | +----+ | | | | +----+ | |OTSi | | +----+ | | | | +----+ | |OTSi
OTSi| o-| |-o | +-----+ | o-| |-o |sink OTSi| o-| |-o | +-----+ | o-| |-o |sink
src | | | | | ===+-+ +-+==| | | | | O---|R src | | | | | ===+-+ +-+==| | | | | O---|R
skipping to change at page 20, line 17 skipping to change at page 19, line 17
| | link | | link | | link | | link
| Matrix |o- - - - - - - - - - o| Matrix |o- - - - - - | Matrix |o- - - - - - - - - - o| Matrix |o- - - - - -
+--------------+ +--------------+ +--------------+ +--------------+
| +---------+ | | +---------+ |
| | Media | | | | Media | |
|o----| Channel |-----o| |o----| Channel |-----o|
| | | |
| Matrix | | Matrix |
+---------+ +---------+
Figure 14: MRN/MLN Topology View with TE Link / FA Figure 14: Topology View with TE Link / FA
Note that there is only one media layer switch matrix (one Note that there is only one media layer switch matrix (one
implementation is a FlexGrid ROADM) in SSON, while a signal layer LSP implementation is a FlexGrid ROADM) in SSON, while a signal layer LSP
(Network Media Channel) is established mainly for the purpose of (Network Media Channel) is established mainly for the purpose of
management and control of individual optical signals. Signal layer management and control of individual optical signals. Signal layer
LSPs with the same attributes (such as source and destination) can be LSPs with the same attributes (such as source and destination) can be
grouped into one media-layer LSP (media channel): this has advantages grouped into one media-layer LSP (media channel): this has advantages
in spectral efficiency (reduce guard band between adjacent OChs in in spectral efficiency (reduce guard band between adjacent OChs in
one FSC channel) and LSP management. However, assuming some network one FSC channel) and LSP management. However, assuming some network
elements perform signal layer switching in an SSON, there must be elements perform signal layer switching in an SSON, there must be
enough guard band between adjacent OTSis in any media channel to enough guard band between adjacent OTSis in any media channel to
compensate filter concatenation effect and other effects caused by compensate for the filter concatenation effects and other effects
signal layer switching elements. In such a situation, the separation caused by signal layer switching elements. In such a situation, the
of the signal layer from the media layer does not bring any benefit separation of the signal layer from the media layer does not bring
in spectral efficiency or in other aspects, but makes the network any benefit in spectral efficiency or in other aspects, but makes the
switch and control more complex. If two OTSis must be switched to network switch and control more complex. If two OTSis must be
different ports, it is better to carry them by diferent FSC channels, switched to different ports, it is better to carry them by diferent
and the media layer switch is enough in this scenario. FSC channels, and the media layer switch is enough in this scenario.
As discussed in Section 3.2.5, a media channel may be constructed As discussed in Section 3.2.5, a media channel may be constructed
from a compsite of network media channels. This may be achieved in from a compsite of network media channels. This may be achieved in
two ways using LSPs. These mechanisms may be compared to the two ways using LSPs. These mechanisms may be compared to the
techniques used in GMPLS to support inverse multiplexing in Time techniques used in GMPLS to support inverse multiplexing in Time
Division Multiplexing (TDM) networks and in OTN [RFC4606], [RFC6344], Division Multiplexing (TDM) networks and in OTN [RFC4606], [RFC6344],
and [RFC7139]. and [RFC7139].
o In the first case, a single LSP may be established in the control o In the first case, a single LSP may be established in the control
plane. The signaling messages include information for all of the plane. The signaling messages include information for all of the
skipping to change at page 24, line 8 skipping to change at page 23, line 8
o A downstream node cannot foresee what an upstream node will o A downstream node cannot foresee what an upstream node will
allocate. A way to ensure that the effective frequency slot is allocate. A way to ensure that the effective frequency slot is
valid along the length of the LSP is to ensure that the same value valid along the length of the LSP is to ensure that the same value
of n is allocated at each hop. By forcing the same value of n we of n is allocated at each hop. By forcing the same value of n we
avoid cases where the effective frequency slot of the media avoid cases where the effective frequency slot of the media
channel is invalid (that is, the resulting frequency slot cannot channel is invalid (that is, the resulting frequency slot cannot
be described by its n and m parameters). be described by its n and m parameters).
o This may be too restrictive, since a node (or even a centralized/ o This may be too restrictive, since a node (or even a centralized/
combined RSA entity) may be able ensure that the resulting end-to- combined RSA entity) may be able to ensure that the resulting end-
end effective frequency slot is valid even if n varies locally. to-end effective frequency slot is valid even if n varies locally.
That means, the effective frequency slot that characterizes the That means, the effective frequency slot that characterizes the
media channel from end to end is consistent and is determined by media channel from end to end is consistent and is determined by
its n and m values, but that the effective frequency slot and its n and m values, but that the effective frequency slot and
those values are logical (i.e., do not map direct to the those values are logical (i.e., do not map direct to the
physically assigned spectrum) in the sense that they are the physically assigned spectrum) in the sense that they are the
result of the intersection of locally-assigned frequency slots result of the intersection of locally-assigned frequency slots
applicable at local components (such as filters) each of which may applicable at local components (such as filters) each of which may
have assigned different frequency slots. have assigned different frequency slots.
For Figure 15 the effective slot is made valid by ensuring that the For Figure 15 the effective slot is made valid by ensuring that the
skipping to change at page 30, line 5 skipping to change at page 29, line 5
grid network grid network
full interworking of fixed and flexible grid devices within the full interworking of fixed and flexible grid devices within the
same network same network
interworking of flexgrid devices with different capabilities. interworking of flexgrid devices with different capabilities.
The information model is represented using Routing Backus-Naur Format The information model is represented using Routing Backus-Naur Format
(RBNF) as defined in [RFC5511]. (RBNF) as defined in [RFC5511].
<Available Spectrum in Fiber for frequency slot> ::= <Available Spectrum> ::=
<Available Frequency Range-List> <Available Frequency Range-List>
<Available Central Frequency Granularity > <Available Central Frequency Granularity >
<Available Slot Width Granularity> <Available Slot Width Granularity>
<Minimal Slot Width> <Minimal Slot Width>
<Maximal Slot Width> <Maximal Slot Width>
<Available Frequency Range-List> ::= <Available Frequency Range-List> ::=
<Available Frequency Range> [<Available Frequency Range-List>] <Available Frequency Range> [<Available Frequency Range-List>]
<Available Frequency Range> ::= <Available Frequency Range> ::=
( <Start Spectrum Position> <End Spectrum Position> ) | ( <Start Spectrum Position> <End Spectrum Position> ) |
<Sets of contiguous slices> <Sets of contiguous slices>
<Available Central Frequency Granularity> ::= (2^n) x 6.25GHz <Available Central Frequency Granularity> ::= (2^n) x 6.25GHz
where n is positive integer, giving rise to granularities where n is a non negative integer, giving rise to granularities
such as 6.25GHz, 12.5GHz, 25GHz, 50GHz, and 100GHz such as 6.25GHz, 12.5GHz, 25GHz, 50GHz, and 100GHz
<Available Slot Width Granularity> ::= (2^m) x 12.5GHz <Available Slot Width Granularity> ::= (2^m) x 12.5GHz
where m is positive integer where m is positive integer
<Minimal Slot Width> ::= j x 12.5GHz, <Minimal Slot Width> ::= j x 12.5GHz,
j is a positive integer j is a positive integer
<Maximal Slot Width> ::= k x 12.5GHz, <Maximal Slot Width> ::= k x 12.5GHz,
k is a positive integer (k >= j) k is a positive integer (k >= j)
skipping to change at page 31, line 28 skipping to change at page 30, line 28
be able to configure local frequency slots. be able to configure local frequency slots.
The control plane architecture SHOULD allow for the support of L-band The control plane architecture SHOULD allow for the support of L-band
and S-band. and S-band.
The signalling process SHALL be able to collect the local frequency The signalling process SHALL be able to collect the local frequency
slot assigned at each link along the path. slot assigned at each link along the path.
The signaling procedures SHALL support all of the RSA architectural The signaling procedures SHALL support all of the RSA architectural
models (R&SA, R+SA, and R+DSA) within a single set of protocol models (R&SA, R+SA, and R+DSA) within a single set of protocol
objects although some objects may only be applicable within on of the objects although some objects may only be applicable within one of
models. the models.
5.1.2. Routing 5.1.2. Routing
The routing protocol will support all functions as described in The routing protocol will support all functions as described in
[RFC4202] and extend them to a flexi-grid data plane. [RFC4202] and extend them to a flexi-grid data plane.
The routing protocol SHALL distribute sufficient information to The routing protocol SHALL distribute sufficient information to
compute paths to enable the signaling procedure to establish LSPs as compute paths to enable the signaling procedure to establish LSPs as
described in the previous sections. This includes, at a minimum the described in the previous sections. This includes, at a minimum the
data described by the Information Model in Figure 17. data described by the Information Model in Figure 17.
skipping to change at page 35, line 35 skipping to change at page 34, line 35
Optics CTO Optics CTO
Via Trento 30 20059 Vimercate (Milano) Italy Via Trento 30 20059 Vimercate (Milano) Italy
+39 039 6863033 +39 039 6863033
sergio.belotti@alcatel-lucent.com sergio.belotti@alcatel-lucent.com
Yao Li Yao Li
Nanjing University Nanjing University
wsliguotou@hotmail.com wsliguotou@hotmail.com
Fei Zhang Fei Zhang
ZTE Huawei
Zijinghua Road, Nanjing, China zhangfei7@huawei.com
zhang.fei3@zte.com.cn
Lei Wang Lei Wang
ZTE wang.lei@bupt.edu.cn
East Huayuan Road, Haidian district, Beijing, China
wang.lei131@zte.com.cn
Guoying Zhang Guoying Zhang
China Academy of Telecom Research China Academy of Telecom Research
No.52 Huayuan Bei Road, Beijing, China No.52 Huayuan Bei Road, Beijing, China
zhangguoying@ritt.cn zhangguoying@ritt.cn
Takehiro Tsuritani Takehiro Tsuritani
KDDI R&D Laboratories Inc. KDDI R&D Laboratories Inc.
2-1-15 Ohara, Fujimino, Saitama, Japan 2-1-15 Ohara, Fujimino, Saitama, Japan
tsuri@kddilabs.jp tsuri@kddilabs.jp
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